Device for eliminating silent periods between intermittent recordings



May 15, 1951 M. HANDSCHIN 2,553,410

DEVICE FOR ELIMINATING SILENT PERIODS BETWEEN INTERMITTENT RECORDINGS Filed Jan. 17, 1947 v H, A 15 17 78 1.9 20 wvs q u 1 my 5 U32 v 5038 Tag spxas NK '2 NKI4 I ve NTOR;

Max Hana/sch! ATTORNEHS Patented May 15, 1951 DEVICE FOR ELIMINATING SILENT PERIODS BETWEEN INTERMITTENT RECORDINGS Max Handschin, Kusnacht-Zurich, Switzerland, assignor to Ipsophon Patentgesellschaft A.-G., of Glarus, a Swiss company Application January 17, 1947, Serial No. 722,603 In Switzerland January 19, 1946 3 Claims. (01. 179-1001) The known types of apparatus for the recording of impulses, as for instance, so-called dictaphones, telephonographs, and also the devices which record trains of impulses of other types on sound-carriers, possess the great disadvantage that if somewhat prolonged intervals elapse between the individual recordings, considerable portions of the sound-carrier are run off without being utilised. One result of this is that, in order to record given lengths of trains of impulses, the sound-carrier has to be made disproportionately long, and another is that, when reproduction takes place, it includes, naturally, the intervals which occurred during the recording process.

The object of the present invention is the creation of a device with which it is sought to eliminate these disadvantages. This object is achieved, in accordance with the invention, by the provision of electrical agencies for the supervision of the incoming impulses, which said electrical agencies, when the impulses cease to arrive, operate a time-limit coupling set to function for a pre-determined period, at the end of which agencies provided for the winding back of as much of the carrier which receives the impulse-recordings as has been run off in this pre-determined time are operated, the apparatus being switched ofi when the process of winding back is completed.

For the supervision of the incoming impulses a speech control relay with time-lag can conveniently be used. The time-limit coupling can also take the form of a time-lag relay. When the time-limit coupling comes into operation, cam-discs are set in rotation through gearing, the contacts of which cam-discs switch ofi the microphone at the end of a predetermined period and effect the switching off and, subsequently thereto, the winding back of the wiredrum and, when the winding back is completed, the switching Off of the apparatus itself.

The enclosed drawing depicts a typical embodiment of a device in accordance with the present invention.

Let it be assumed that the microphone T39 is connected to an impulse-recording apparatus, and that a calling current excites the relay R2 in the known manner through the circuit:

(1) Microphone T39, contact 11, condenser K031, relay R2, contact i8, microphone T39.

Through the excitation of the relay R2, relay HI is excited through the following circuit:

(2) Battery positive, contact 22, contact 2i, relay HI, operating winding, battery negative.

Relay I-ll locks via the circuit:

'Nl, battery negative.

(3) Battery positive, cam contact 28, contact 20, relay Hi, holding winding, battery negative. Through the excitation of relay Hi, relay F3 is excited, which through its contact 25 excites the mains relay N4. Through this the motor 'MIE is connected up to the mains and operates in the known manner gearing which is not depicted in the drawing.

Relay F3 is excited through the circuit: (4) Battery positive, contact l6, relay F3, operating winding, battery negative.

Relay F3 is held through the circuit: (5) Battery positive, cam contact 29, contact 2|, relay F3, holding winding, battery negative. The mains relay N4 is excited from the circuit: (6) Battery positive, contact 25, mains relay The motor is excited by the circuit:

(7) Mains, contact 26, motor Ml5, mains; 1

Through the excitation of relay Hi the 'for- Ward coupling VKB of the sound-carrier is en'- gaged with the forward-running gear. The wiredrum BT36 is driven forward in the direction shown by the arrow. The wire SD38 is wound from wire-drum DT3'I on to wire-drum DT36. The forward coupling is excited from the circuit:

(8) Battery positive, contact l9, forward coupling VKG, battery negative.

The microphone T39 can now deliver a recording, or message, in the known manner, to the impulse-recording apparatus, through the circuit:

(9) Microphone T39, contact 11, repeater U32, amplifier V33, speech recording-head SPK35 and back through amplifier V33, repeater U32, contact l8, to microphone T39.

Parallelly to the repeater U32, the speech control relay K5 is excited via the impulse amplifier JV34, i. e., the time-lag relay K5 remains excited whilst the speech impulses of the microphone T39 are arriving. If the person speaking now hangs up having completed the recording, i. e.. if the microphone T39 passes on no further speech impulses, the speech control relay K5 becomes dead.

Through the dropping of relay K5 contact 21 is closed and thus the time-limit coupling ZK8 is switched on through the circuit:

(10) Battery positive, contact 23, contact 21, time-limit coupling ZKB, battery negative.

Through the excitation of the time-limit coupling ZK8 the cam-discs NKS9, NKSIO and NKSH are driven by means of a gearing, in the direction indicated by the arrow. The soundcarrier (wire-drum DT36) continues to turn. It

.irom relay the speech recording head SPK35 and amplifiers V33 and JV34 (circuit 9).

If contact 30 is now closedby the cams I4, the reverse coupling RKT is engaged with thegearing. Wire-drum DT31 is unwoundin't-he direction opposite to that indicatedby arromior a period of, say 10 seconds 1ThEIEVQPSEBOHPHI-1g RKI is excited from the circuit:

, (11) Battery positive, reverse .coupling .RK'L battery negative.

If contact 30 is opened, circuit 1 l "becomes dead once more.

Finally, cam NKI3 will open contact 29, with the result that theholding current is cut off Through this, circuits of the relays F3 and N4 and the motorMHi also become dead, and the impulse-recording apparatus is ready for .further recordings.

The "device hereinsdescr-ibed and depicted prevents the sound-carrier from continuing .to run whilst not being used. On the contrary, its entire length is utilised .-for the recording .of .suc-

.cessively recorded impulse-signals or messages,

so that reproduction of the recording Without intervals 10f silence becomes possible.

.Iszlaim:

1. Adevicerfor the recording of electrical audio signals, comprising :a recording head, .a record 'narrier, an electrically operated drive for moving said record carrier forwardly and rearward-1y relatively :tosaid recording -.head, a time 1 delay switch :control means for said time delay switch responsive to :the ceasing of the signals to be recorded and becoming qperativeaafter -a com- -=paratively short interval ,and a comparatively longer time interval after the ceasing :oi itheisignals to berecordedand electrical circuit ,meams connecting said time delay switch with c :said ;driyeto.=switch off'theforward drive and to switch cnthe rearward'drive when the time .de-

lay switch becomes operative after said comparativelyshort timeinterval, :and to switch 'ofi :xthe ;,r,earwar.d drive when the time delay switch --becomes operative after said longer time interval, whereby the return movement of the record carrier which is thus "produced substantially :co- Iincides with the forward-movement thereof duringlsaid short time interval.

2. In a device for the .reccrjding of electrical audio signals in combination, :a recording head, a record carrier cooperating with the recording iieadrforthe recording of the signals, a drive for advancing said record carrier with respect to the recording head, means for reversing the direction'of movementof the record carrier, 2. time delay control device (comprising electrical relay means responsive to the signals ibeing recorded,

driving means to be actuated by said relay means after the ceasing of signals to be recorded, control means operatively connected with said driving means and operable by the latter for a fixed interval a predetermined time after the actuation of the driving means, to operate .said means .iorreversing the direction of movement of the record carrier during said interval, the lengths of said predetermined time and of said interval being chosen, to effect a reverse movement of ."the record carrier substantially equal to its forward movement occurring after the ceasing of eig-na-lsto ,be recorded.

a subscriber station of a telephone sysitem in combination, a recording head, a record .carrier cooperating with the recording head for recording electrical audio signals arriving over the line, driving means for advancing the record carrier ina forward direction with respect to the recording head, further driving means for advancing the record carrier .in a :backward v:direc- .tion'with respect to the recording head, a ringing set responsive to ringing currents arriving over the line to start the first-named driving means, .a time delay control device comprising electrical relay means responsive to the signals being recorded, a source ofmotion to be started by said relay :means after the .cea-sing of audio signals arriving over the line, a first control means operatively connected with said source of motion to be rendered inoperative a predeterminedtime after the ceasing (if-audio signals :a-r-

riving over the line and adapted to maintain its operative position :the first-named driving means actuated independent of saidringing :set, and a second control :means operativel-y con- --nected withsaid source of motion, to berendered operative duringa predetermined time, whensaid first control :means is in its inoperative position and adapted :to maintain its operative :position .said further driving means actuated toreverse the movement :of the record carrier andto stop this reverse movement, when the position of the record carrier substantially coincides with its position at the ceasing of :audio signals arriving over theline.

MAX HANDSCHIN.

REFERENCES CITED The vfollow-ing references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 1,454,157 Egerton May 8, 1923 1,971,028 Bothe Aug. 21, 1934 2,004,893 Hall June 11, 1 935 2,314,834 Kiel Mar. 28, 194.3 2,348,204 Brubaker May 9, 1944 FOREIGN PATENTS .Number Country Date 278,991 Italy Oct. 27, 19:30 

